On the basis of a long-term(30 years) field experiment that involved four rotation systems, rice-rice-winter fallow(RRF), rice-rice-ryegrass(RRG), rice-rice-rape(RRP), and rice-rice-milk vetch(RRV), this stu...On the basis of a long-term(30 years) field experiment that involved four rotation systems, rice-rice-winter fallow(RRF), rice-rice-ryegrass(RRG), rice-rice-rape(RRP), and rice-rice-milk vetch(RRV), this study described the effects of green manure on the microbial communities in the red paddy soils using 454 pyrosequencing for the 16 S r RNA gene. The Chao1 richness and non-parametric Shannon's index increased in all soil samples that received green manure treatments. The communities' structures with the green manure applications were significantly dissimilar from that under the winter fallow. Using Metastats tests, many genera in the RRG, RRP and RRV soils were significantly different from those in the RRF soil, including a number of genera that functioned in the nitrogen and sulfur cycles. Analyses of the genera with these functions revealed the shifts in microbial ecosystem functions after long-term green manuring. Changes in the microbial communities increased the ammonium supply and decreased the soil acidification in green-manure-amended soils. Together, these data suggested powerful effects of green manure on both the microbial communities and the biogeochemical cycle driven by the shifts in bacterial functional groups.展开更多
During the period of dry nursery seedling raising of late double cropping indica rice in South China, both chemical fertilizer and farmyard manure did not show obvious effect on the growth of shoot and root in young s...During the period of dry nursery seedling raising of late double cropping indica rice in South China, both chemical fertilizer and farmyard manure did not show obvious effect on the growth of shoot and root in young seedlings at 4-leaf stage (18-day-old seedling), but had significant effects on root growth in old seedlings with 6-7 leaves (27-day-old seedling) at suitable seeding densities (65-125g m<sup>-2</sup>). There were satistically significant differences (at 0.01 or 0.05 levels)between treatments in root number and rooting ability of root-pruned seedlings.展开更多
Dissimilatory Fe(Ⅲ) reduction is an important process in the geochemical cycle of iron in anoxic environment. As the main products of dissimilatory iron reduction, the Fe(Ⅱ) species accumulation could indicate t...Dissimilatory Fe(Ⅲ) reduction is an important process in the geochemical cycle of iron in anoxic environment. As the main products of dissimilatory iron reduction, the Fe(Ⅱ) species accumulation could indicate the reduction ability. The effects of different green manures on Fe(Ⅲ) reduction in paddy soil were explored based on a 31-year rice-rice-winter green manure cropping experiment. Four treatments were involved, i.e., rice-rice-milk vetch (RRV), rice-rice-rape (RRP), rice-rice-ryegrass (RRG) and rice-rice-winter fallow (RRF). Soils were sampled at flowering stage of milk vetch and rape (S1), before transplantation (S2), at tillering (S3), jointing (S4), and mature (S5) stages of the early rice, and after the harvest of the late rice (S6). The contents of TFeHa (HCI-extractable total Fe), Fe(Ⅱ)HCI (HCI-extractable Fe(Ⅱ) species) and Fe(Ⅲ)HCI (HCI- extractable Fe(Ⅲ) species) were measured. The correlations among those Fe species with selected soil environmental factors and the dynamic characteristics of Fe(Ⅱ)HCI accumulation were investigated. The results showed that TFeHc~ in RRF was significantly higher than those in the green manure treatments at most of the sampling stages. Fe(II)Ha increased rapidly after the incorporation of green manures in all treatments and kept rising with the growth of early rice. Fe(Ⅱ)Ha in RRG was quite different from those in other treatments, i.e., it reached the highest at the S2 stage, then increased slowly and became the lowest one at the S4 and S5 stages. Fe(Ⅲ)Ha showed oppositely, and Fe(Ⅱ)HCI/Fe(Ⅲ)HCI performed similarly to Fe(Ⅱ)HCI The maximum accumulation potential of Fe(Ⅱ)HCI was significantly higher in RRF, while the highest maximum reaction rate of Fe(Ⅱ)Ha accumulation appeared in RRG. Significant correlations were found between the indexes of Fe(Ⅱ)HCI accumulation and soil pH, oxidation-reduction potential (Eh) and total organic acids, respectively. In together, we found that long-term application of green manures decreased the TFeHa in red paddy soils, but promoted the ability of Fe(lll) reduction, especially the ryegrass; Fe(Ⅱ)Ha increased along with the growth of rice and was affected by soil conditions and environmental factors, especially the water and redox ability.展开更多
基金supported by the Special Fund for Agro-scientific Research in the Public Interest of China(201103005)the Science and Technology Innovation Project of Chinese Academy of Agricultural Sciences(2013–2017)
文摘On the basis of a long-term(30 years) field experiment that involved four rotation systems, rice-rice-winter fallow(RRF), rice-rice-ryegrass(RRG), rice-rice-rape(RRP), and rice-rice-milk vetch(RRV), this study described the effects of green manure on the microbial communities in the red paddy soils using 454 pyrosequencing for the 16 S r RNA gene. The Chao1 richness and non-parametric Shannon's index increased in all soil samples that received green manure treatments. The communities' structures with the green manure applications were significantly dissimilar from that under the winter fallow. Using Metastats tests, many genera in the RRG, RRP and RRV soils were significantly different from those in the RRF soil, including a number of genera that functioned in the nitrogen and sulfur cycles. Analyses of the genera with these functions revealed the shifts in microbial ecosystem functions after long-term green manuring. Changes in the microbial communities increased the ammonium supply and decreased the soil acidification in green-manure-amended soils. Together, these data suggested powerful effects of green manure on both the microbial communities and the biogeochemical cycle driven by the shifts in bacterial functional groups.
文摘During the period of dry nursery seedling raising of late double cropping indica rice in South China, both chemical fertilizer and farmyard manure did not show obvious effect on the growth of shoot and root in young seedlings at 4-leaf stage (18-day-old seedling), but had significant effects on root growth in old seedlings with 6-7 leaves (27-day-old seedling) at suitable seeding densities (65-125g m<sup>-2</sup>). There were satistically significant differences (at 0.01 or 0.05 levels)between treatments in root number and rooting ability of root-pruned seedlings.
基金supported by the Special Fund for Agroscientific Research in the Public Interest,China(201103005)the Science and Technology Innovation Project of Chinese Academy of Agricultural Sciences(2013–2017)
文摘Dissimilatory Fe(Ⅲ) reduction is an important process in the geochemical cycle of iron in anoxic environment. As the main products of dissimilatory iron reduction, the Fe(Ⅱ) species accumulation could indicate the reduction ability. The effects of different green manures on Fe(Ⅲ) reduction in paddy soil were explored based on a 31-year rice-rice-winter green manure cropping experiment. Four treatments were involved, i.e., rice-rice-milk vetch (RRV), rice-rice-rape (RRP), rice-rice-ryegrass (RRG) and rice-rice-winter fallow (RRF). Soils were sampled at flowering stage of milk vetch and rape (S1), before transplantation (S2), at tillering (S3), jointing (S4), and mature (S5) stages of the early rice, and after the harvest of the late rice (S6). The contents of TFeHa (HCI-extractable total Fe), Fe(Ⅱ)HCI (HCI-extractable Fe(Ⅱ) species) and Fe(Ⅲ)HCI (HCI- extractable Fe(Ⅲ) species) were measured. The correlations among those Fe species with selected soil environmental factors and the dynamic characteristics of Fe(Ⅱ)HCI accumulation were investigated. The results showed that TFeHc~ in RRF was significantly higher than those in the green manure treatments at most of the sampling stages. Fe(II)Ha increased rapidly after the incorporation of green manures in all treatments and kept rising with the growth of early rice. Fe(Ⅱ)Ha in RRG was quite different from those in other treatments, i.e., it reached the highest at the S2 stage, then increased slowly and became the lowest one at the S4 and S5 stages. Fe(Ⅲ)Ha showed oppositely, and Fe(Ⅱ)HCI/Fe(Ⅲ)HCI performed similarly to Fe(Ⅱ)HCI The maximum accumulation potential of Fe(Ⅱ)HCI was significantly higher in RRF, while the highest maximum reaction rate of Fe(Ⅱ)Ha accumulation appeared in RRG. Significant correlations were found between the indexes of Fe(Ⅱ)HCI accumulation and soil pH, oxidation-reduction potential (Eh) and total organic acids, respectively. In together, we found that long-term application of green manures decreased the TFeHa in red paddy soils, but promoted the ability of Fe(lll) reduction, especially the ryegrass; Fe(Ⅱ)Ha increased along with the growth of rice and was affected by soil conditions and environmental factors, especially the water and redox ability.